856664 has 16 divisors (see below), whose sum is σ = 1701000. Its totient is φ = 403072.

The previous prime is 856649. The next prime is 856693. The reversal of 856664 is 466658.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3014 + ... + 3285.

856664 is a Friedman number, since it can be written as 8+6^6+(6*5)^4, using all its digits and the basic arithmetic operations.

2⁸⁵⁶⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

856664 is a deficient number, since it is larger than the sum of its proper divisors (844336).

856664 is a wasteful number, since it uses less digits than its factorization.

856664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6322 (or 6318 counting only the distinct ones).

The product of its digits is 34560, while the sum is 35.

The square root of 856664 is about 925.5614512284. The cubic root of 856664 is about 94.9737323498.

The spelling of 856664 in words is "eight hundred fifty-six thousand, six hundred sixty-four".